Rachna borrowed a certain sum at the rate of 15% per annum. if she paid at the end of the two years Rs.1290 as interest Compounded annually, find the sum she borrowed.

Given info:

Compound Interest = Rs.1290

Rate of Interest = 15% p.a

Time = 2 years

Where

C.I = Compound Interest

P = Principle

R = Rate of Interest

N = Time

Here

C.I = Rs.1290

R = 15%

N = 2 years

Principle = ?

Now,Calculating the sum (Principle) borrowed by Rachna

Substituting the given values

Hence,

The sum (Principle) is Rs.4000.